KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 43. N:o 10. 9 
It is at last interesting, in respect to our ideas here proposed, to recall in mind 
an opinion, expressed by W. HUGGINS,' viz., — that the gaseous nebulxe may possibly 
belong to an order of cosmical bodies, distinct from that represented by the sun and 
the fixed stars. As I was acquainted with this memoir of HUGGINS after having 
formed my opionion, referred to above, on the resemblance and the probable identity 
in general structure of the Galaxy and the planetary nebule, the hypothesis 
gains in probability. 
4. Nuclei of Bing Nebulce. 
The nuclei of most of the Ring Nebulze as for example the Ring Nebula in 
Lyra, G.C. 4447, have a peculiar spectrum of yellow and green light, in such a 
degree as to make it necessary considerably to adjust the eyepiece to see the 
nucleus. According to KEELER”, there can hardly be any doubt that the central star is 
actually formed from the nebula by a process of condensation; but it is not merely 
a brigther portion of the nebula, emitting radiations of the same character as the 
rest, the nucleus being so nearly approaching to the stellar character that the general 
distribution of light in its spectrum is that of an ordinary star. According to photo- 
graphs taken by J. SCcHEINER” and E. GOTHARD'”, similar centres are shown in the 
nebulae G.C. 4628 and G. C. 4964." These facts are in accordance with our concep- 
tions of the original state of the Galactic System and of its having in the centre 
a particular body of globular clusters, condensed in the singular manner above re- 
ferred to. 
The nuclei of the Ring Nebulzx are, moreover, frequently very slight and faint, 
compared with the whole of the nebulous body, as even is the case with the Glo- 
bular Clusters” System compared with the Galactic System on the whole. 
5. Various forms of Planetary Nebulce. 
The most conspicuous of the planetary nebul&e is the Ring Nebula G.OC. 4447 
in Lyra. "The adjoined reproduction of this nebula, Plate 5 N:o 5, shows the ne- 
bula in the form, ascribed to it by the late Miss CLERKE and others, as exhibiting 
rather an open than a closed ring, similar to the typographic sign of a big parenthesis, 
with a slight nucleus in the middle. An even more striking example of ring nebula is 
offered by the pale planetary nebula G. C. 2343, which is of considerable size. The adjoined 
photograph of this nebula, Plate 5 N:o 1, shows the nebula to be nearly of the same 
1! S. HuGGIns, On the spectra of some of the nebule. Proceedings of the Royal Society, Vol. 156:1, 
1866, pag. 392. 
> KEELER, On the central star of the Ring Nebula in Lyra. Astr. Nachr. N:o 3111. 
> J. ScHetserR, Uber die planetarischen Nebel h 2098 [G.C. 4628] und h 2241 [G.C. 4964] Astr. 
Nachr. N:o 3086. 
+ E. GoTHARD, Photographische Aufnahmen Astr. Nachr. Vol. 113 pag. 221. 
K. Sv. Vet. Akad. Handl. Band 43. N:o 10. 
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